What do AQI numbers mean?

The AQI is a scale from 0 to 500 that is used to measure air pollution levels. The higher the number, the worse the air quality and the greater the potential health risks. An AQI greater than 100 means air quality is not within the health-based air quality standards established by the EPA.

Our local air quality agency, Spokane Regional Clean Air Agency, measures these common pollutants found in Spokane's air:

• Particulate Matter (PM2.5 and PM10) – fine particles from wildfire smoke, dust, or vehicle emissions
• Ground-level ozone (O3)

How to Read and Understand AQI Categories

• AQI 0–50: Good (Green): Air quality is considered satisfactory, and pollution poses little or no risk to anyone. It’s safe to spend time outdoors and
• AQI 51–100: Moderate (Yellow): Air quality is acceptable for most people. However, individuals who are unusually sensitive to air pollution may experience mild symptoms with prolonged exposure.
• AQI 101–150: Unhealthy for Sensitive Groups (Orange): Members of sensitive groups—including children, teens, adults over 65, pregnant individuals, and people with heart or lung conditions—may experience negative health impacts from breathing air outside. These groups should limit outdoor activity and plan to spend as much time as possible in a clean air environment.
• AQI 151–200: Unhealthy (Red): Everyone may begin to experience health effects. Sensitive groups are at greater risk and should avoid outdoor exposure whenever possible.
• AQI 201–300: Very Unhealthy (Purple): This level triggers a county-wide health alert. All of us are at risk of experiencing more serious health impacts after spending unmasked time outside, and sensitive individuals should stay indoors and avoid all outdoor activities.
• AQI 301–500: Hazardous (Maroon): This is considered an emergency situation in Spokane. Everyone should avoid going outside, and every household should have a cleaner air room to spend time in.

Where to Check AQI in Spokane

You can monitor current air quality at Spokane Clean Air, which is updated hourly. You can sign up for alerts and check air quality across the country, as well as wildfires, at AirNow.gov.

How to Use the AQI Information

• The Washington Department of Health has an Air Quality Guide for Particle Pollution, which provides AQI-based recommendations to reduce exposure to PM2.5.
• The current AQI is updated hourly and can change quickly due to wind shifts.
• Use AQI to plan activities: Adjust outdoor plans depending on current and forecasted AQI levels.

Why AQI Is Especially Important for Sensitive Groups

Children, pregnant individuals, seniors, and people with chronic conditions like asthma or heart disease are more sensitive to air pollution. Even "moderate" AQI levels can trigger symptoms or health effects in these groups.

How we monitor Spokane's air:

What to Do When AQI is Unhealthy

• Limit or avoid time outdoors
• Keep doors and windows closed
• If you don't have a way to stay cool in the heat, find shelter elsewhere.
• Use a HEPA air cleaner or set up a clean room in your home
• Avoid outdoor exercise or prolonged activity
• Wear a properly fitted N95 mask if you must go outside
• Check in on vulnerable family members or neighbors.